Process for the preparation of 1,1,1,3,3-pentafluoropropane and 1,1,1,3,3,3-hexafluoropropane

ABSTRACT

A process for the manufacture of CF 3 CH 2 CHF 2  and CF 3 CH 2 CF 3  is disclosed. The process involves (a) reacting HF and at least one halopropene of the formula CX 3 CCl═CClX (where each X is independently F or Cl) to produce a product including both CF 3 CCl═CF 2  and CF 3 CHClCF 3 ; (b) reacting CF 3 CCl═CF 2  and CF 3 CHClCF 3  produced in (a) with hydrogen to produce a product including both CF 3 CH 2 CHF 2  and CF 3 CH 2 CF 3 ; and (c) recovering CF 3 CH 2 CHF 2  and CF 3 CH 2 CF 3  from the product produced in (b). In (a), the CF 3 CCl═CF 2  and CF 3 CHClCF 3  are produced in the presence of a fluorination catalyst including a ZnCr 2 O 4 /crysta α-chromium oxide composition, a ZnCr 2 O 4 /crystalline α-chromium oxide composition which has been treated with a flourinating a agent, a zinc halide/α-chromium oxide composition and/or a zinc halideα-chromium oxide composition which has been treated with a fluorinating agent.

FIELD OF THE INVENTION

This invention relates to the synthesis of 1,1,1,3,3-pentaflouropropaneand 1,1,1,3,3,3-hexafluoropropane.

BACKGROUND

A number of chlorine-containing halocarbons are considered to bedetrimental toward the Earth's ozone layer. There is a world-wide effortto develop materials having lower ozone depletion potential that canserve as effective replacements. For example, the hydrofluorocarbon,1,1,1,2-tetraflouroethane (HFC-134a) is being used as a replacement fordichlorodifluoromethane (CFC-12) in refrigeration systems. There is aneed for manufacturing processes that provide halogenated hydrocarbonsthat contain less chlorine or no chlorine. The production ofhydrofluorocarbons (i.e., compounds containing only carbon, hydrogen andfluorine), has been the subject of considerable interest to provideenvironmentally desirable products for use as solvents, blowing agents,refrigerants, cleaning agents, aerosol propellants, heat transfer media,dielectrics, fire extinguishants and power cycle working fluids. Forexample, 1,1,1,3,3-pentafluoropropane has utility as a blowing agent,and 1,1,1,3,3,3-hexafluoropropane has utility as a fire extinguishantand as a refrigerant.

SUMMARY OF THE INVENTION

This invention provides a process for the manufacture of1,1,1,3,3-pentaflouropropane (HFC-245fa) and1,1,1,3,3,3-hexafluoropropane (HFC-236fa). The process comprises (a)reacting HF and at least one halopropene of the formula CX₃CCl═CClX,wherein each X is independently selected from the group consisting of Fand Cl, to produce a product comprising CF₃CCl═CF₂ and CF₃CHClCF₃,wherein said CF₃CCl═CF₂ and CF₃CHClCF₃ are produced in the presence of afluorination catalyst comprising at least one composition selected fromthe group consisting of (i) compositions comprising ZnCr₂O₄ andcrystalline α-chromium oxide, (ii) compositions comprising a zinc halideand α-chromium oxide and (iii) compositions of (i) or (ii) which havebeen treated with a fluorinating agent (e.g., anhydrous hydrogenfluoride); (b) reacting CF₃CCl═CF₂ and CF₃CHClCF₃ produced in (a) withhydrogen (H₂), optionally in the presence of HF, to produce a productcomprising CF₃CH₂CHF₂ and CF₃CH₂CF₃; and (c) recovering CF₃CH₂CHF₂ andCF₃CH₂CF₃ from the product produced in (b).

DETAILED DESCRIPTION

This invention provides a process for the preparation of CF₃CH₂CHF₂(HFC-245fa) and CF₃CH₂CF₃ (HFC-236fa). The HFC-245fa and HFC-236fa maybe recovered as individual products and/or as one or more mixtures ofthe two products.

In step (a) of the process of this invention, one or more halopropenecompounds CX₃CCl═CClX, wherein each X is independently selected from thegroup consisting of F and Cl, are reacted with hydrogen fluoride (HF) toproduce a product mixture comprising CF₃CCl═CF₂ (CFC-1215xc) andCF₃CHClCF₃ (HCFC-226da). Accordingly, this invention provides a processfor the preparation of mixtures of CF₃CCl═CF₂ (CFC-1215xc) andCF₃CHClCF₃ (HCFC-226da) from readily available starting materials.

Suitable starting materials for the process of this invention includeE-and Z-CF₃CCl═CClF (CFC-1214xb), CF₃CCl═CCl₂ (CFC-1213xa),CClF₂CCl═CCl₂ (CFC-1212xa), CCl₂FCCl═CCl₂ (CFC-121 1xa), andCCl₃CCl═CCl₂ (hexachloropropene, HCP), or mixtures thereof.

Due to their availability, CF₃CCl═CCl₂ (CFC-1213xa) and CCl₃CCl═CCl₂(hexachloropropene, HCP) are the preferred starting materials for theprocess of the invention.

Preferably, the reaction of HF with CX₃CCl═CClX is carried out in thevapor phase in a heated tubular reactor. A number of reactorconfigurations are possible, including vertical and horizontalorientation of the reactor and different modes of contacting thehalopropene starting material(s) with HF. Preferably the HF issubstantially anhydrous.

In one embodiment of step (a), the halopropene starting material(s) maybe fed to the reactor containing the fluorination catalyst. Thehalopropene starting material(s) may be initially vaporized and fed tothe reactor as gas(es).

In another embodiment of step (a), the halopropene starting material(s)may be contacted with HF in a pre-reactor. The pre-reactor may be empty(i.e., unpacked), but is preferably filled with a suitable packing suchas Monel™ or Hastelloy™ nickel alloy turnings or wool, or other materialinert to HCl and HF which allows efficient mixing of CX₃CCl═CClX and HF.

If the halopropene starting material(s) are fed to the pre-reactor asliquid(s), it is preferable for the pre-reactor to be orientedvertically with CX₃CCl═CClX entering the top of the reactor andpre-heated HF vapor introduced at the bottom of the reactor.

Suitable temperatures for the pre-reactor are within the range of fromabout 80° C. to about 250° C., preferably from about 100° C. to about 5200° C. Under these conditions, for example, hexachloropropene isconverted to a mixture containing predominantly CFC-1213xa. The startingmaterial feed rate is determined by the length and diameter of thereactor, the temperature, and the degree of fluorination desired withinthe pre-reactor. Slower feed rates at a given temperature will increasecontact time and tend to increase the amount of conversion of thestarting material and increase the degree of fluorination of theproducts.

The term “degree of fluorination” means the extent to which fluorineatoms replace chlorine substituents in the CX₃CCl═CClX startingmaterials. For example, CF₃CCl═CClF represents a higher degree offluorination than CClF₂CCl═CCl₂ and CF₃CHClCF₃ represents a higherdegree of fluorination than CClF₂CHClCF₃.

The molar ratio of HF fed to the pre-reactor, or otherwise to thereaction zone of step (a), to halopropene starting material fed in step(a), is typically from about stoichiometric to about 50:1. Thestoichiometric ratio depends on the average degree of fluorination ofthe halopropene starting material(s) fed to the pre-reactor and istypically based on formation of C₃ClF₅. For example, if the halopropeneis HCP, the stoichiometric ratio of HF to HCP is 5:1; if the halopropeneis CFC-1213xa, the stoichiometric ratio of HF to CFC-1213xa is 2:1.Preferably, the molar ratio of HF to halopropene starting material isfrom about twice the stoichiometric ratio (based on formation of C₃ClF₅)to about 30:1. Higher ratios than 30:1 are not particularly beneficial.Lower ratios of HF to halopropene result in reduced yields of CFC-1215xcand HCFC-226da. Typically, for a given catalyst, higher HF feed ratioswill tend to favor formation of HCFC-226da relative to CFC-121 5xc.

In a preferred embodiment of this invention, in step (a) of the process,the halopropene starting materials are vaporized, preferably in thepresence of HF, contacted with HF in a pre-reactor, and then contactedwith the fluorination catalyst. If the preferred amount of HF is fed inthe pre-reactor, additional HF is not required when the effluent fromthe pre-reactor contacts the fluorination catalyst.

Suitable temperatures for catalytic fluorination of halopropene startingmaterials and/or their products formed in the pre-reactor are within therange of about 200° C. to about 400° C., preferably from about 240°C. toabout 350° C. Higher temperatures typically contribute to reducedcatalyst life. Temperatures below about 2400C. may result in substantialamounts of products having a degree of fluorination less than five(i.e., underfluorinates). Suitable reactor pressures for vapor phaseembodiments of this invention may be in the range of from about 1 toabout 30 atmospheres. Reactor pressures of about 5 atmospheres to about20 atmospheres may be advantageously employed to facilitate separationof HCl from other reaction products in step (b) of the process.

The fluorination catalysts which are used in the process of the presentinvention are preferably compositions comprising ZnCr₂O₄ (zinc chromite)and crystalline α-Cr₂O₃ (α-chromium oxide) or compositions obtained bytreatment of said compositions comprising ZnCr₂O₄ (zinc chromite) andcrystalline α-Cr₂O₃ (α-chromium oxide) with a fluorinating agent. Theamount of zinc relative to the total of chromium and zinc in thesecompositions is preferably from about 1 atom % to about 25 atom %.

Of note are chromium-containing catalyst compositions comprising ZnCr₂O₄(zinc chromite) and crystalline α-chromium oxide wherein the ZnCr₂O₄contains between about 10 atom percent and 67 atom percent of thechromium in the composition and at least about 70 atom percent of thezinc in the composition, and wherein at least about 90 atom percent ofthe chromium present as chromium oxide in the composition is present asZnCr₂O₄ or crystalline α-chromium oxide. Also of note arechromium-containing catalyst compositions, prepared by treatment of suchcompositions comprising ZnCr₂O₄ and crystalline α-chromium oxide with afluorinating agent. Also of note are such chromium-containing catalystcompositions which comprise ZnCr₂O₄ and crystalline α-chromium oxidewherein the ZnCr₂O₄ contains between about 20 atom percent and about 50atom percent of the chromium in the composition. Also of note are suchchromium-containing catalyst compositions which comprise ZnCr₂O₄ andcrystalline α-chromium oxide wherein the ZnCr₂O₄ contains at least about90 atom percent of the zinc in the composition. Also of note are suchchromium-containing catalyst compositions comprising zinc chromite andcrystalline α-chromium oxide wherein greater than 95 atom percent of 35the chromium that is not present as zinc chromite is present ascrystalline α-chromium oxide. Also of note are such chromium-containingcatalyst compositions which consist essentially of ZnCr₂O₄ (zincchromite) and crystalline α-chromium oxide.

These compositions may be prepared, for example, by co-precipitationmethods followed by calcination.

In a typical co-precipitation procedure, an aqueous solution of zinc andchromium(lll) salts is prepared. The relative concentrations of the zincand chromium(lll) salts in the aqueous solution is dictated by the bulkatom percent zinc relative to chromium desired in the final catalyst.Therefore, the concentration of zinc in the aqueous solution is fromabout 1 mole % to about 25 mole % of the total concentration of zinc andchromium in the solution. The concentration of chromium(lll) in theaqueous solution is typically in the range of 0.3 to 3 moles per literwith 0.75-1.5 moles per liter being a preferred concentration. Whiledifferent chromium (Ill) salts might be employed, chromium(lll) nitrateor its hydrated forms such as [Cr(NO₃)₃(H₂O)₉], are the most preferredchromium(lll) salts for preparation of said aqueous solution.

While different zinc salts might be employed for preparation of saidaqueous solutions, preferred zinc salts for preparation of catalysts forthe process of this invention include zinc(ll) nitrate and its hydratedforms such as [Zn(NO₃)₂(H₂O)₆].

The aqueous solution bf the chromium(lll) and zinc salts may then beevaporated either under vacuum or at elevated temperature to give asolid which is then calcined.

It is preferred to treat the aqueous solution of the chromium(lll) andzinc salts with a base such as ammonium hydroxide (aqueous ammonia) toprecipitate the zinc and chromium as the hydroxides. Bases containingalkali metals such as sodium or potassium hydroxide or the carbonatesmay be used but are not preferred. The addition of ammonium hydroxide tothe aqueous solution of the chromium(lll) and zinc salts is typicallycarried out gradually over a period of 1 to 12 hours. The pH of thesolution is monitored during the addition of base. The final pH istypically in the range of 6.0 to 11.0, preferably from about 7.5 toabout 9.0, most preferably about 8.0 to about 8.7. The precipitation ofthe zinc and chromium hydroxide mixture is typically carried out at atemperature of about 15° C. to about 60° C., preferably from about 20°C. to about 40° C. After the ammonium hydroxide is added, the mixture istypically stirred for up to 24 hours. The precipitated chromium and zinchydroxides serve as precursors to ZnCr₂O₄ and α-chromium oxide.

After the precipitation of the zinc and chromium hydroxide mixture iscomplete, the mixture is dried. This may be carried out by evaporationin an open pan on a hot plate or steam bath or in an oven or furnace ata suitable temperature. Suitable temperatures include temperatures fromabout 60° C. to about 130° C. (for example, about 100° C. to about 120°C.). Alternatively, the drying step may be carried out under vacuumusing, for example, a rotary evaporator.

Optionally, the precipitated zinc and chromium hydroxide mixture may becollected and, if desired, washed with deionized water before drying.Preferably the precipitated zinc and chromium hydroxide mixture is notwashed prior to the drying step.

After the zinc and chromium hydroxide mixture has been dried, thenitrate salts are then decomposed by heating the solid from about 250°C. to about 350° C. The resulting solid is then calcined at temperaturesof from about 400° C. to about 1000° C., preferably from about 400° C.to about 900° C.

Further information on the zinc and chromium compositions useful forthis invention is provided in U.S. patent application 60/511,353 [CL2244US PRV] filed Oct. 14, 2003, and hereby incorporated by reference hereinin its entirety (see also corresponding International Application No.PCT/US2004/).

The calcined zinc chromite/α-chromium oxide compositions of the presentinvention may be pressed into various shapes such as pellets for use inpacking reactors. It may also be used in powder form.

Typically, the calcined compositions will be pre-treated with afluorinating agent prior to use as catalysts for changing the fluorinecontent of halogenated carbon compounds. Typically this fluorinatingagent is HF though other materials may be used such as sulfurtetrafluoride, carbonyl fluoride, and fluorinated carbon compounds suchas trichlorofluoromethane, dichlorodifluoromethane,chlorodifluoromethane, trifluoromethane, or1,1,2-trichlorotrifluoroethane. This pretreatment can be accomplished,for example, by placing the catalyst in a suitable container which canbe the reactor to be used to perform the process in the instantinvention, and thereafter, passing HF over the dried, calcined catalystso as to partially saturate the catalyst with HF. This is convenientlycarried out by passing HF over the catalyst for a period of time, forexample, about 0.1 to about 10 hours at a temperature of, for example,about 200° C. to about 450° C. Nevertheless, this pretreatment is notessential.

Other catalysts suitable for the fluorinations of step (a) arecompositions comprising a zinc halide and α-chromium oxide andcompositions obtained by treatment of said compositions comprising azinc halide and α-chromium oxide with a fluorinating agent. U.S. Pat.No. 3,878,257 discloses an example of such catalysts. The amount of zincrelative to the total of chromium and zinc in these compositions ispreferably from about 0.1 atom % to about 25 atom %; and is morepreferably from about 2 atom % to about 10 atom %. Of note arecompositions wherein a zinc halide is supported on a support comprisingα-chromium oxide. Preferably, the α-chromium oxide is prepared accordingto U.S. Pat. No. 5,036,036. Pretreatment with a fluorinating agent canbe carried out as indicated above for the calcined zincchromite/α-chromium oxide compositions.

Compounds that are produced in the fluorination process in step (a)include the CF₃CCl═CF₂ (CFC-1215xc) and CF₃CHClCF₃ (HCFC-226da).

Halopropane by-products having a higher degree of fluorination thanHCFC-226da that may be formed in step (a) include CF₃CClFCF₃(CFC-217ba).

Halopropane by-products having a lower degree of fluorination thanHCFC-226da that may be formed in step (a) include CF₃CHClCClF₂(HCFC-225da). Other halopropane by-products which may be formed includeCFC-216aa (CF₃CC1₂CF₃).

Halopropene by-products having a lower degree of fluorination thanCFC-1215xc that may be formed in step (a) include E-and Z-CF ₃CCl═CClF(CFC-1214xb) and CF₃CCl═CCl₂ (CFC-1213xa).

Typically, the effluent from step (a) comprising CFC-1215xc andHCFC-226da, and optionally HF, is separated from lower boilingcomponents, mainly comprising HCl along with some over-fluorinatedproducts such as CFC-217ba and azeotropic HF, and from the higherboiling components comprising the under-fluorinated components such asHCFC-225da, C₃Cl₄F₄ isomers, and CFC-1213xa.

In one embodiment of the process of this invention, the reactor effluentfrom step (a) may be delivered to a distillation column in which HCl andany HCl azeotropes are removed from the top of column while the higherboiling components are removed at the bottom of the column. The productsrecovered at the bottom of the first distillation column are thendelivered to a second distillation column in which CFC-217ba, and someHF, are separated at the top of the column and the remaining HF andorganic products, comprising CF₃CHClCF₃, CF₃CCl═CF₂, and higher boilingcomponents, are removed from the bottom of the column. The productsrecovered from the bottom of the second distillation column are thendelivered to a third distillation column in which CF₃CHClCF₃,CF₃CCl═CF₂, and HF, are separated at the top of the column, and anyremaining HF and under-fluorinated components are removed from thebottom of the column.

The mixture of CF₃CHClCF₃, CF₃CCl═CF₂, and HF, from the top of the thirddistillation column may be delivered to step (b) or may optionally bedelivered to a decanter maintained at a suitable temperature to causeseparation of an organic-rich liquid phase and an HF-rich liquid phase.

The HF-rich phase may be distilled to recover HF which is then recycledto step (a). The organic-rich phase may then be delivered to step (b) ormay be distilled to give pure HCFC-226da and CFC-1215xc.

In one embodiment of the process of this invention saidunder-flourinated components such as HCFC-225da, C₃Cl₂F₄, andCF₃CCl═CCl₂ (CFC-1213xa) may be returned to step (a).

In step (b) of the process, the CF₃CHClCF₃ and CF₃CCl═CF₂ produced instep (a) are reacted with hydrogen (H₂), optionally in the presence ofHF.

In one embodiment of step (b), a mixture comprising CF₃CHClCF₃ andCF₃CCl═CF₂, and optionally HF, is delivered in the vapor phase, alongwith hydrogen (H₂), to a reactor fabricated from nickel, iron, titanium,or their alloys, as described in U.S. Pat. No. 6,540,933; the teachingsof this disclosure are incorporated herein by reference. A reactionvessel of these materials (e.g., a metal tube) optionally packed withthe metal in suitable form may also be used. When reference is made toalloys, it is meant a nickel alloy containing form 1 to 99.9% (byweight) nickel, an iron alloy containing 0.2 to 99.8% (by weight) iron,and a titanium alloy containing 72-99.8% (by weight) titanium. Of noteis use of an empty (unpacked) reaction vessel made of nickel or alloysof nickel such as those containing 40% to 80% nickel, e.g., Inconel™ 600nickel alloy, Hastelloy™ C617 nickel alloy, or Hastelloy™ C276 nickelalloy.

When used for packing, the metal or metal alloys may be particles orformed shapes such as perforated plates, rings, wire, screen, chips,pipe, shot, gauze, or wool.

The temperature of the reaction in this embodiment can be between about35° C. and about 600° C., and is preferably at least about 450° C.

The molar ratio of hydrogen to the CFC-1215xc/HCFC-226da mixture fed tothe reaction zone should be in the range of about 0.1 mole H₂ per moleof CFC-1215xc/HCFC-226da mixture to about 60 moles of H₂ per mole ofCFC-1215xc/HCFC-226da mixture, more preferably from about 0.4 to 10moles of H₂ per mole of CFC-1215xc/HCFC-226da mixture.

In another embodiment of the process, the contacting of hydrogen withthe CFC-1215xc/HCFC-226da mixture produced in step (a), and optionallyHF, is carried out in the presence of a hydrogenation catalyst.Hydrogenation catalysts suitable for use in this embodiment includecatalysts comprising at least one metal selected from the groupconsisting of rhenium, iron, ruthenium, osmium, cobalt, rhodium,iridium, nickel, palladium, and platinum. Said catalytic metal componentis typically supported on a carrier such as carbon or graphite or ametal oxide, fluorinated metal oxide, or metal fluoride where thecarrier metal is selected from the group consisting of magnesium,aluminum, titanium, vanadium, chromium, iron, and lanthanum.

Of note are carbon supported catalysts in which the carbon support hasbeen washed with acid and has an ash content below about 0.1% by weight.Hydrogenation catalysts supported on low ash carbon are described inU.S. Pat. No. 5,136,113, the teachings of which are incorporated hereinby reference. Also of note are catalysts comprising at least one metalselected from the group consisting of palladium, platinum, and rhodiumsupported on alumina (Al₂O₃), fluorinated alumina, or aluminum fluoride(AlF₃).

The supported metal catalysts may be prepared by conventional methodsknown in the art such as by impregnation of the carrier with a solublesalt of the catalytic metal (e.g., palladium chloride or rhodiumnitrate) as described by Satterfield on page 95 of HeterogenousCatalysis in Industral Practice, 2^(nd) edition (McGraw-Hill, N.Y.,1991). The concentration of the catalytic metal(s) on the support istypically in the range of about 0.1% by weight of the catalyst to about5% by weight.

The relative amount of hydrogen contacted with CFC-1215xc and HCFC-226dawhen a hydrogenation catalyst is used is typically from about thestoichiometric ratio of hydrogen to CF₃CHClCF₃/CF₃CCl═CF₂ mixture toabout 10 moles of H₂ per mole of CF₃CHClCF3/CF₃CCl═CF₂ mixture.

The stoichiometric ratio of hydrogen to the CF₃CHClCF₃/CF₃CCl═CF₂mixture depends on the relative amounts of the two components in themixture. The stoichiometric amounts of H₂ required to convert HCFC-226daand CFC-1215xc to CF₃CH₂CF₃ and CF₃CH₂CHF₂, are one and two moles,respectively.

Suitable temperatures for the catalytic hydrogenation are typically fromabout 100° C. to about 350° C., preferably from about 125° C. to about300° C. Temperatures above about 350° C. tend to result indefluorination side reactions; temperatures below about 125° C. willresult in incomplete substitution of Cl for H in the starting materials.The reactions are typically conducted at atmospheric pressure orsuperatmospheric pressure.

The products from the step (b) reaction zone(s) typically include HCl,CF₃CH₂CF₃ (HFC-236fa), CF₃CH₂CHF₂ (HFC-245fa), and small amounts oflower boiling by-products (typically including propane, CF₃CH═CF₂(HFC-1225zc), E-and Z-CF₃CH═CHF (HFC-1234ze), and/or CF₃CH₂CH₃(HFC-263fb)) and higher boiling by-products and intermediates (typicallyincluding CF₃CHFCH₃ (HFC-254eb) and/or CF₃CHClCHF₂ (HCFC-235da)) as wellas any unconverted starting materials and any HF carried over from step(a).

In step (c), the desired products are recovered. Products from step (b)may be delivered to a separation unit to recover CF₃CH₂CF₃ andCF₃CH₂CHF₂ individually, as a mixture, or as their HF azeotropes.

Partially chlorinated components such as HCFC-235da may be recovered andrecycled back to step (b).

The reactor, distillation columns, and their associated feed lines,effluent lines, and associated units used in applying the processes ofthis invention should be constructed of materials resistant to hydrogenfluoride and hydrogen chloride. Typical materials of construction,well-known to the fluorination art, include stainless steels, inparticular of the austenitic type, the well-known high nickel alloys,such as Monel™ nickel-copper alloys, Hastelloy™ nickel-based alloys and,lnconel™ nickel-chromium alloys, and copper-clad steel.

The following specific embodiments are to be construed as merelyillustrative, and do not constrain the remainder of the disclosure inany way whatsoever.

EXAMPLES

LEGEND 215aa is CF₃CCl₂CClF₂ 216aa is CF₃CCl₂CF₃ 217ba is CF₃CClFCF₃225da is CF₃CHClCClF₂ 226da is CF₃CHClCF₃ 1213xa is CF₃CCl═CCl₂ 1214 isC₃Cl₂F₄ 1215xc is CF₃CCl═CF₂

Catalyst Preparation Comparative Preperation Example 1 Preparation of100% Chromium Catalyst (400° C.)

A solution of 400 g Cr(NO₃)₃[9(H₂O)] (1.0 mole) in 1000 mL of deionizedwater was treated dropwise with 477 mL of 7.4M aqueous ammonia raisingthe pH to about 8.5. The slurry was stirred at room temperatureovernight. After re-adjusting the pH to 8.5 with ammonia, the mixturewas poured into evaporating dishes and dried in air at 120° C. The driedsolid was then calcined in air at 400° C.; the resulting solid weighed61.15 g. The catalyst was pelletized (−12 to +20 mesh, (1.68 to 0.84mm)) and 28.2 g (20 mL) was used in Comparative Example 1.

Comparative Preperation Example 2 Preparation of 2% Zinc on AluminaCatalyst

Aluminum oxide (4.90 moles, Harshaw 3945, dried at 110° C.) was added toa solution of 20.85 g ZnCl₂ (0.153 mole) dissolved in 460 mL ofdistilled water. Water was evaporated from the mixture with stirring andthen dried at 110° C. for three days. The catalyst was pelletized (−12to +20 mesh, (1.68 to 0.84 mm)) and 21.1 g (30 mL) was used inComparative Example 3.

Preperation Example 1 Preparation of 2% Zinc Chloride Supported onChromium Oxide

A solution of 1.20 g ZnCl₂ (8.81 moles) in 60 mL of deionized water 30contained in a 125 mm×65 mm glass dish was treated with 60.00 g (0.357mole) of 12-20 mesh Cr₂O₃. The dish was placed on a warm hot plate andthe slurry allowed to dry with occasional stirring. The resulting solidwas then dried overnight at 130° C.; the resulting solid weighed 60.42g. The catalyst was pelletized (−12 to +20 mesh, (1.68 to 0.84 mm)) and41.5 g (30 mL) was used in Example 1.

Preperation Example 2 Preperation of 95%Chromium/5% Zinc Catalyst (450°C.)

A solution of 380.14 g Cr(NO₃)₂[6(H₂O)] (0.950 mole) and 14.87 gZn(NO₃)₂[6(H₂O)] (0.050 mole) was prepared in 1000 mL of deionizedwater. The solution was treated with 450 mL of 7.4M aqueous ammoniumhydroxide over the course of one hour; the pH increased from 1.7 to pH8.4. The slurry was stirred at room temperature overnight and then driedat 120° C. in an oven in the presence of air. The dried solid was thencalcined in air at 450° C. for 20 hours; the resulting solid weighed76.72 g. The catalyst was pelletized (−12 to +20 mesh, (1.68 to 0.84mm)) and 38.5 g (25 mL) was used in Example 6.

Preperation Example 3 Preparation of 90% Chromium/10% Zinc Catalyst(900° C.)

A solution of 360.13 g Cr(NO₃)₃[9(H₂O)] (0.900 mole) and 29.75 gZn(NO₃)₂[6(H₂O)] (0.100 mole) was prepared in 1000 mL of deionizedwater. The solution was treated with 450 mL of 7.4M aqueous ammoniumhydroxide over the course of 1.4 hours; the pH increased from 1.9 to pH8.4. The slurry was stirred at room temperature overnight and then driedat 120° C. in the presence of air. The dried solid was then calcined inair at 20 900° C. for 20 hours; the resulting solid weighed 75.42 g. Thecatalyst was pelletized (−12 to +20 mesh, (1.68 to 0.84 mm)) and 42.3 g(25 mL) was used in Example 8.

Preperation Example 4 Preparation of 95%Chromium/5% Zinc Catalyst (900°C.)

A solution of 380.14 g Cr(NO₃)₃[9(H₂O)] (0.950 mole) and 14.87 gZn(NO₃)₂[6(H₂O)] (0.050 mole) was prepared in 1000 mL of deionizedwater. The solution was treated with 450 mL of 7.4M aqueous ammoniumhydroxide over the course of one hour; the pH increased from 1.7 to pH8.4. The slurry was stirred at room temperature overnight and then driedat 120° C. in an oven in the presence of air. The dried solid was thencalcined in air at 900° C. for 20 hours; the resulting solid weighed70.06 g.

The catalyst was pelletized (−12 to +20 mesh, (1.68 to 0.84 mm)) and25.3 g (14 mL) was used in Example 7.

Preperation Example 5 Preparation of 98% Chromium/2% Zinc Catalyst (900°C.)

A solution of 392.15 g Cr(NO₃)₃[9(H₂O)] (0.980 mole) and 5.94 gZn(NO₃)₂[6(H₂O)] (0.020 mole) was prepared in 1000 mL of deionizedwater. The solution was treated with 450 mL of 7.4M aqueous ammoniumhydroxide over the course of 0.58 hour; the pH increased from 1.67 to pH8.35. The slurry was stirred at room temperature overnight and thendried at 120° C. in an oven in the presence of air. The dried solid wasthen calcined in air at 900° C. for 21 hours; the resulting solidweighed 66.00 g. The catalyst was pelletized (−12 to +20 mesh, (1.68 to0.84 mm)) and 44.9 g (23 mL) was used in Example 5.

Preperation Example 6 Preparation of 10% Zinc Chloride Supported onChromium Oxide

A solution of 6.0 g ZnCl₂ (44 moles) in 300 mL of deionized watercontained in a 170 mm×90 mm glass dish was treated with 60.00 g (0.357mole) of 12-20 mesh Cr₂O₃. The dish was placed on a warm hot plate andthe slurry allowed to dry with occasional stirring. The resulting solidwas then dried overnight at 130° C.; the resulting solid weighed 65.02g. The catalyst was pelletized (−12 to +20 mesh, (1.68 to 0.84 mm)) and37.5 g (25 mL) was used in Example 2.

Preperation Example 7 Preparation of 98.1% Chromium/1.9% Zinc Catalyst(550° C.)

A solution of 516.46 g Cr(NO₃)₃[9(H₂O)] (1.29 moles) and 7.31 gZn(NO₃)₂[6(H₂O)] (0.0246 mole) was prepared in 500 mL of distilled waterin 1L beaker resting on a hot plate. The mixture was then transferred toa Pyrex™ container and the container placed in a furnace. The containerwas heated from room temperature to 125° C. at 10° C./min and then heldat 125° C. for six hours. The container was heated from 125° C. to 350°C. at 1° C./min and then held at 350° C. for six hours. The containerwas heated from 350° C. to 550° C. at 1° C./min and then held at 550° C.for 24 hours. The catalyst was pelletized (−12 to +20 mesh, (1.68 to0.84 mm)) and 29.9 g (20 mL) was used in Examples 3 and 4.

Examples 1-8 and Comparative Examples 1-3 General Procedure forFluorination

A weighed quantity of pelletized catalyst was placed in a 5/8″(1.58 cm)diameter lnconel™ nickel alloy reactor tube heated in a fluidized sandbath. The tube was heated from 50° C. to 175° C. in a flow of nitrogen(50 cc/min; 8.3(10)⁻⁷m³/sec) over the course of about one hour. HF wasthen admitted to the reactor at a flow rate of 50 cc/min(8.3(10)⁻⁷m³/sec). After 0.5 to 2 hours the nitrogen flow was decreasedto 20 cc/min (3.3(10)⁻⁷m³/sec) and the HF flow increased to 80 cc/min(1.3(10) ⁻⁶m³/sec); this flow was maintained for about 1 hour. Thereactor temperature was then gradually increased to 400° C. over 3 to 5hours. At the end of this period, the HF flow was stopped and thereactor cooled to 300° C. under 20 sccm (3.3(10)⁻⁷m³/sec) nitrogen flow.CFC-121 3xa was fed from a pump to a vaporizer maintained at about 11 8°C. The CFC-1213xa vapor was combined with the appropriate molar ratiosof HF in a 0.5 inch (1.27 cm) diameter Monel™ nickel alloy tube packedwith Monel™ turnings. The mixture of reactants then entered the reactor;the contact time was 15 seconds unless otherwise indicated. Allreactions were conducted at a nominal pressure of one atmosphere. Theresults of CFC-1213xa fluorination over the several catalysts are shownin Table 1; analytical data is given in units of GC area %. TABLE 1 Exa.HF/1213 Temp Products, GC Area % No. Ratio ° C. Catalyst 1215xc 217ba226da 216aa 225da 1214's 1213xa 1^(a) 20/1 260 2% ZnCl₂/Cr₂O₃ 65.9 —19.9 0.9 1.60 3.3 4.8 2^(a)  6/1 280 10% ZnCl₂/Cr₂O₃ 42.4 — 1.2 0.04 2.815.4 37.7 3^(b) 20/1 300 Cr/Zn 98.1/1.9 550° C. 20.1 0.3 64.2 9.1 1.61.6 0.8 4 20/1 350 Cr/Zn 98.1/1.9 550° C. 7.9 0.4 77.2 11.2 0.2 0.7 0.45  6/1 280 Cr/Zn 98/2 900° C. 34.8 — 1.1 0.04 2.5 16.4 44.6 6^(b)  6/1280 Cr/Zn 95/5 450° C. 1.3 0.01 73.0 6.5 0.4 1.3 1.5 7 30/1 320 Cr/Zn95/5 900° C. 79.0 — 5.9 0.3 — 4.0 8.7 8 20/1 280 Cr/Zn 90/10 900° C.70.3 — 10.2 1.0 3.1 8.1 6.6 C1^(c) 20/1 300 100% Cr₂O₃ 0.3 0.9 89.7 7.8— 8.1 6.6 C2^(a,c,d) 20/1 300 100% Cr₂O₃ (HSA) 0.2 — 94.5 3.9 — — —C3^(a,c)  6/1 280 2% Zn/Al₂O₃ 2.5 0.02 90.5 0.02 1.4 1.4 3.2^(a)The contact time was 30 seconds.^(b)Product contained 12.8 GC area % CFC-215aa.^(c)Comparative Example.^(d)High surface area chromium oxide from a commercial source; thecatalyst was activated with HF prior to use following the generalprocedure.

1. A process for the manufacture of 1,1,1,3,3-pentafluoropropane and 1,1,1,3,3,3-hexafluoropropane, comprising: (a) reacting HF and at least one halopropene of the formula CX₃CCl═CClX, wherein each X is independently selected from the group consisting of F and Cl, to produce a product comprising CF₃CCl═CF₂ and CF₃CHClCF₃, wherein said CF₃CCl═CF₂ and CF₃CHClCF₃ are produced in the presence of a fluorination catalyst comprising at least one composition selected from the group consisting of (i) compositions comprising ZnCr₂O₄ and crystalline α-chromium oxide, (ii) compositions comprising a zinc halide and α-chromium oxide and (iii) compositions of (i) or (ii) which have been treated with a fluorinating agent; (b) reacting CF₃CCl-CF₂ and CF₃CHClCF₃ produced in (a) with hydrogen to produce a product comprising CF₃CH₂CHF₂ and CF₃CH₂CF₃; and (c) recovering CF₃CH₂CHF₂ and CF₃CH₂CF₃ from the product produced in (b).
 2. The process of claim 1 wherein in (a) the catalyst is selected from the group consisting of (i) compositions comprising ZnCr₂O₄ and crystalline α-chromium oxide and (iii) compositions of (i) which have been treated with a fluorinating agent.
 3. The process of claim 2 wherein the amount of zinc relative to the total of chromium and zinc in the catalyst composition is from about 1 atom % to about 25 atom %.
 4. The process of claim 2 wherein the catalyst is selected from the group consisting of (i) compositions comprising ZnCr2O4 and crystalline 60 -chromium oxide wherein the ZnCr2O₄ contains between about 10 atom percent and 67 atom percent of the chromium in the composition and at least about 70 atom percent of the zinc in the composition, and wherein at least about 90 atom percent of the chromium present as chromium oxide in the composition is present as ZnCr2O₄ or crystalline α-chromium oxide and (iii) compositions of (i) which have been treated with a fluorinating agent.
 5. The process of claim 1 wherein in (a) the catalyst is selected from the group consisting of (ii) compositions comprising a zinc halide and α-chromium oxide and (iii) compositions of (ii) which have been treated with a fluorinating agent.
 6. The process of claim 5 wherein the amount of zinc relative to the total of chromium and zinc in the catalyst composition is from about 0.1 atom % to about 25 atom %.
 7. The process of claim 5 wherein the catalyst is selected from the group consisting of (ii) compositions wherein a zinc halide is supported on a support comprising α-chromium oxide and (iii) compositions of (ii) which have been treated with a fluorinating agent; and wherein the amount of zinc relative to the total of chromium and zinc in the catalyst composition is from about 2 atom % to about 10 atom %. 